Replace the constructors in net.optifine.expr.FunctionType with
private FunctionType(ExpressionType expressionType, String name, ExpressionType[] parameterTypes)
{
	this.expressionType = expressionType;
	this.name = name;
	this.parameters = new IParameters() {
		@Override
		public ExpressionType[] getParameterTypes(IExpression[] var1) {
			return parameterTypes;
		}
	};
}

private FunctionType(int precedence, ExpressionType expressionType, String name, ExpressionType[] parameterTypes)
{
	this.precedence = precedence;
	this.expressionType = expressionType;
	this.name = name;
	this.parameters = new IParameters() {
		@Override
		public ExpressionType[] getParameterTypes(IExpression[] var1) {
			return parameterTypes;
		}
	};
}

private FunctionType(ExpressionType expressionType, String name, IParameters parameters)
{
	this.expressionType = expressionType;
	this.name = name;
	this.parameters = parameters;
}

private FunctionType(int precedence, ExpressionType expressionType, String name, IParameters parameters)
{
	this.precedence = precedence;
	this.expressionType = expressionType;
	this.name = name;
	this.parameters = parameters;
}


Replace the parseValue method in net.optifine.config.ConnectedParser with
public static Comparable parseValue(String str, Class cls)
{
	switch (cls.getName()) {
		case "java.lang.String":
			return str;
		case "java.lang.Float":
			return Float.valueOf(str);
		case "java.lang.Double":
			return Double.valueOf(str);
		case "java.lang.Integer":
			return Integer.valueOf(str);
		case "java.lang.Long":
			return Long.valueOf(str);
		default:
			return null;
	}
}

Finally, add
if (token == null) return null;
right after
Token token = (Token)deque.peek();
In method getFunctionType in class net.optifine.expr.ExpressionParser